Red violet to violet-blue dye and process of making same.



UNITED STATlE PATENT Ohhftllil.

GADTENT ENGL OF BASEL, SVt'ITZEitTL-XND, ASSlGNQR TO THE SOCiE'lY OF CH MTCAL INDUSTRY lid BASLE, OF BASEL,

LA N1).

Fl RM OF SWITZER 'RED VIOLET TO VIOLET-BLUE DYE AND PROCESS OF MAKlNG SAME.

Specification of Letters Patent.

atented Nov. 20, 1906.

inclination filed May 26,1900- Serial No, 318.833.

alpha-isatinarylides of the general formulaz- The invention is illustrated by the following examples:

Example 1: Three parts of salicylthioacetic acid, 2.5 parts of alpha-isatinanilid, and twenty-five to thirty parts of acetic anhydrid are heated to boiling for three hours in a reflux apparatus. After a short time the solution becomes of a beautiful blueviolet color and the condensation product separates. Its formation results from the condensation of alpha-isatinanilid with thioindoxyl into which the salicylthioacetic acid. is intermediary transformed during the re action. When the reaction is over, the whole is allowed to cool and filtered. The product on the filter is washed with alcohol and dried. The dyestuff is thus obtained directly in a pure form as lustrous blueviolet felted needles. In concentrated sul furic acid it dissolves to a blue solution hav ing' a green tinge. By diluting the sulfuricacid solution with water the dycstuff is precipitated again unchanged as dark violetblue flocks. In warm benzene it is easily soluble to a red-violet solution having a brown-red fluorescence. lVhen made into a vat with caustic-soda lye and sodiumhydrowhite, the dyestuff yields a bright-yellow vat, from which cotton without a mordant is dyed violet-blue tints. For facilit ating lfltlliing it up into a vat the dyestuif is used in as finely divided 2. form as possible-for inst ance, as a paste. the crystallized dyestuif may be dissolved in To obtain it in such a condition,

228 ccntigrade.

concentrated sulfuric acid and reprecipitated with water, or it may be made up into an alkaline vat and precipitated by introducing air, whereupon the iiocculent. precipitated product may be filtered,

Example II: Two parts of thioindoxyl,

three parts of alpha-isatinanilid, and thirty I parts of acetic anhydrid are heated to boiling for two to thyee hours in a reflux apparatus in an oil-bath. After cooling,the dyestuff, which has crystallized, is filtered, washed with alcohol, and dried. it forms violet-red crystals, which dissolve in concentrated sulfuric acid to a blue-green solution.

' The solution in benzene is violet-red and has a fairly intense yellow-red fluorescence. In an alkaline hydrosulfite vat the dyestufi' dyes cotton without a mordant red-violet tints of remarkable fastness'.

lxample III: Two parts of thioindoxyl, 1.5 parts of alpha-isatinanilid, and twenty parts of nitrobenzene are heated for one and one-half hours in a reflux apparatus in an oil-bath the temperature of which is 225 to the dyestuff, which has crystallized, is filtered, washed with alcohol, and dried.

After the mass has cooled When made up into an alkaline vat, it dyes cotton without a mordant blue-violet tints,

Example IV: To two parts of thioindoxyl dissolved in alcohol is added an alcoholic solution of three parts of isatinanilid. After this mixture has been boiled for a short time 0.3 to 0.5 parts of sodium carbonate are added and the mass is boiled during some minutes, whereby the reaction product separates in form of bluish-violet crystals, which are isolated by filtration,-washed with alcohol to eliminate the adherent sodium carbonate, and dried. The dyestufi' constitutes a bluish-violet crystalline powder, dyeing unmordanted' cotton in an alkaline hydrosuli'ite vat violet blue tints. In analogous manner dyestuffs may be manufactured from other alphaisatinarylids, such as alpha-isatin-orthotoluidid or: alpha or ,beta naphthyl isat-inarylids.

, What I claim is 1. The herein-describcd process for the manufacture of red violet to violet-blue vate with alpha isatinerylids of the general formule:

oNH Ar i. CO

Asnew products, the red iolet to violetblue vat dyeing dyestuffs resulting from the condensation of thioindoxyl with alphaisetinarylids, the said dyestufis giving with concentrated sulfuric acid blue solutionsfro n which the dyestuffs are precipitated un changed by addition of water, and dissolving in hot benzene with violet red to redviolet coloration.

In witness whereof I have hereunto signed my name, this 14th day of May, 1906, in the presence of two subscribing witnesses.

GADIENT ENGI.

Witnesses:

GEO. GIFFoRn, AMAND BITTER. 

